AUTONOMOUS DATA ACQUISITION SYSTEMS

WIDEBAND ACOUSTIC MEASUREMENT SYSTEM

SRB-16 RECORDING BUOY

REMOTE ACOUSTIC MEASUREMENT BUOY

The HTI Wideband Acoustic Measurement System is a single channel, wide band, portable, shallow water buoy system intended primarily for making shallow water acoustic measurements. The system may be repeatedly deployed in a slack surface buoy mooring in water depths ranging from 20 to 1000 feet (6.1 to 304.8 meters).

The buoy system consists of a buoyant float assembly, an electronics package with VHF and UHF antennas, an omnidirectional hydrophone with an electromechanical extension cable, and a rechargeable battery pack.

Underwater signals are received by the hydrophone and transmitted to the shipboard telemetry system via a VHF radio transmission where the data is transferred to a data handling system.

The buoy electronics are powered by a self-contained battery power supply.

Multiple single channel acoustic monitoring systems may be deployed simultaneously. A shipboard command transmitter may be used to control multiple systems via a UHF radio link as an alternative to the manual controls on the buoy system electronics package.

• sensitivity = -180 dB re 1V/uPa
• frequency response = 10 Hz to 50 kHz
• self-noise (dB re: 1uPa/sq.rt.Hz):
  • 43 dB @ 100 Hz
  • 27 dB @ 1000 Hz
  • 15 dB @ 10,000 Hz
  • 10 dB @ 50,000 Hz
• dynamic range = 110 dB minimum (spectral)
• directionality = omnidirectional to 50 kHz (+/- 3 dB)

• VHF transmit freq. - 136.0-173.5 MHz
• VHF transmit power - 1 Watt
• gain - 0 dB or 20 dB, selectable

• life - 48 hrs.
• supply - 14 VDC, 25 amp-hrs.

• Ambient noise measurements
• Signal/noise characterization
• Marine mammal monitoring
• Acoustic tracking system
• Source signature monitor

SRB-16 AUTONOMOUS RECORDING BUOY

High Tech, Inc. has developed and manufactured autonomous data acquisition systems for recording marine seismic data using vertical or horizontal bottom-mounted cables. These autonomous data acquisition systems consist of:

• A) a multi-channel hydrophone array connected to the electronics buoy by a tether and vertically or horizontally mounted on the sea floor;
• B) the electronics buoys, which include the telemetry link, the data recorder, the power supply, and associated electronics; and
• C) a shipboard interface that can control up to 64 individual buoy systems.

The electronics buoys are configured remotely through an RF telemetry link. A faster RF telemetry link is used to send status information and sample data traces from the electronics buoys back to the ship. Hydrophone array data are recorded on tape in digital format by each electronics buoy. Power for each electronics buoy is supplied by an internal battery pack providing 72 hours of continuous operation. System bandwidth is tailored to suit each customer's application.

These rugged and versatile systems can operate in a variety of underwater environments. Over 60 autonomous data acquisition systems have been purchased for use by the petroleum industry.

Autonomous data acquisition system deployment

• Data channels: 1 to 16
• A/D converter: 24 bit Delta-Sigma
• Gain: selectable; 0 dB, 12 dB, 24 dB, 36 dB, 48 dB
• Channel gain matching: +/- 1%
• Crosstalk: -90 dB maximum
• Input noise: < 1uV RMS
• THD: -90 dB maximum at -3 dB signal level
• Total dynamic range: >132 dB
• Data recorder: Exabyte 8500 with 5 Gigabyte storage capacity

• Battery life:
  • 72 hrs. continuous operation
  • 15 days standby mode

• Type: RF telemetry link
• Range: 7 miles
• Transmit power: 4 watts
• Baud rate: 1200 (buoy configuration), 9600 (data receive)

• RS-232 navigation interface
• TTL or relay closure time break
• RF link transmit power: 24 watts
• Capacity: controls up to 64 autonomous systems

• Operating temperature: 0 deg. C to 40 deg. C
• Storage temperature: -40 deg. C to 85 deg. C
• Shock (operating): 3 g @ 5 ms, 2 g @ 11 ms, 1 g @ 20 ms
• Shock (non-operating): 40 g @ 30 ms
• Humidity: 5% to 95% non-condensing

• RF radio link communicates with autonomous systems up to 7 miles
• Deep water, high sensitivity hydrophones
• Sample data traces available at shipboard interface in pseudo-real time
• Up to 64 individual systems configured from single shipboard interface
• Compact payload for easy deployment, recovery, and servicing
• Electronics buoys individually configurable from shipboard interface:
  • set hydrophone channel gain
  • power mode (standby or full power)
  • transmit system status or data trace
  • activate/deactivate individual hydrophone channels
• 5 Gigabyte capacity digital data recorder
• Standard RS-232 navigation interface
• Standby mode for battery power conservation (up to 15 days)
• Microcontroller-based shipboard interface to electronics buoys
• Tape read systems available

REMOTE ACOUSTIC MEASUREMENT BUOY SYSTEM

The HTI REMOTE ACOUSTIC MEASUREMENT BUOY System is an eight channel, portable, shallow water buoy system intended primarily for making shallow water acoustic measurements. The system may be repeatedly deployed in a slack surface buoy mooring in water depths ranging from 20 to 1000 feet (6.1 to 304.8 meters).

The buoy system consists of a buoyant float assembly, an electronics package with 900 MHz RF and GPS antennas, an omnidirectional hydrophone with an electromechanical extension cable, and a rechargeable battery pack.

Underwater signals are received by the hydrophone recorded to the recording buoy saved as raw binary data files. The status messages and commands are transmitted and received via a 900 MHz RF radio transmission.

The buoy electronics are powered by a self-contained battery power supply.

The shipboard unit consists of a Monitor Control Station (MCS) notebook PC and a GPS notebook PC. Remote buoy status and buoy position is constantly updated at the MCS computer which may be located upto 10 kms from the floating buoy.

The floatation buoy is constantly tracked by a GPS tracking software that tracks the relative distance of the floating buoy from the ship with an accuracy of +1m.

• Data channels: 1 to 8
• SAMPLE RATE: 65536 Hz/channel (User Selectable 1kHz- 65.536kHz)
• A/D converter: 24 bit Delta-Sigma
• Gain: selectable; 0 dB, 12 dB, 24 dB, 36 dB
• Channel gain matching: +/- 1%
• Crosstalk: -90 dB maximum
• Input noise: < 1uV RMS
• THD: -90 dB maximum at -3 dB signal level
• Total dynamic range: >132 dB
• Data recorder: Hitachi Travelstar with 80 Gigabyte storage capacity

• Battery life:
  • 12 hrs. recording operation
  • 24 HRS standby mode

• Type: RF telemetry link
• Range: 10KMS
• Transmit power: 1 watts
• Baud rate: 9600

• Operating temperature: 0 deg. C to 40 deg. C
• Storage temperature: -40 deg. C to 85 deg. C
• Shock (operating): 3 g @ 5 ms, 2 g @ 11 ms, 1 g @ 20 ms
• Shock (non-operating): 40 g @ 30 ms
• Humidity: 5% to 95% non-condensing

• Microcontroller-based shipboard interface to electronics buoys
• RF radio link communicates with autonomous systems up to 10 kms
• Deep water, high sensitivity hydrophones
• Sample data traces available at shipboard interface in pseudo-real time
• Compact payload for easy deployment, recovery, and servicing
• Electronics buoys individually configurable from shipboard interface:
  • set hydrophone channel gain
  • power mode (standby or full power)
  • transmit system status or data trace
  • activate/deactivate individual hydrophone channels
• 80 Gigabyte capacity digital data recorder
• Standby mode for battery power conservation (up to 24 hours)